1. Field of the Invention.
This invention relates, generally, to devices that facilitate the construction of roof trusses, and more specifically relates to such a device that is highway transportable and adjustable in length.
2. Description of the Prior Art.
Devices that make roof trusses fall within two major classifications: fixed position or immobile, and mobile. The former are used in truss making plants that ship the finished product to the job site, whereas the latter allows truss assembly at the site.
The advantages of the latter type of equipment include the ability of the construction foreman at the job site to control the quality of the final product.
A typical fixed position truss-making apparatus is shown in U.S. Pat. No. 3,367,010 to Lytle, et. al.
A typical mobile device is shown in U.S. Pat. No. 4,567,821 to McDonald.
Additional examples of both mobile and immobile truss-making apparatuses are shown in the following U.S. Pat. Nos.: 4,304,046 to McDonald (1981); 3,752,467 to Stanley (1973); 4,453,705 to McDonald (1984); 3,379,354 to Moehlenpah, et. al. (1968); 3,068,484 to Moehlenpah, et. al. (1962); 4,174,061 to McDonald (1979); 4,084,499 to Moehlenpah (1978); and 3,711,007 to Fry (1973).
Although the art is reasonably well developed, the devices of the prior art, although they adequately perform their intended functions, have certain limitations.
In a broad sense, the known immobile devices cannot be transported on public highways, and the known mobile devices lack versatility.
Accordingly, a mobile apparatus having a high degree of versatility is needed. Specifically, there is a need for a mobile device that can be easily extensible as needed to facilitate the construction of very large roof trusses at a job site. The needed device, preferably, would be constructed of stock materials and would therefore be inexpensive to manufacture.
However, the art neither teaches nor suggests how a mobile device having the qualities missing from the structures of the prior art could be constructed.